However, the weldability of these steels has been an ongoing concern due to the high amounts of carbon and other austenite stabilizers, which can produce hard microstructures in the weld zone
since high cooling rates are experienced in RSW.
Cross-section micro-structure photographs of weld zone
are shown in the Figs 2 and 3.
Detail modeling of weld zone
account local effect in this region.
In friction stir welding section, unlike weld zone
by conventional fusion welding, considerable compressive residual stress is built at TMAZ, and some of compressive residual stress and fine tension residual stress are formed in the surface area and the center area of SZ, respectively.
Microstructure samples were machined with 10 mm x 10 mm x 5 mm, which ensured that the specimen contained base metal (BM), heat affected zone (HAZ), and weld zone
The amount of plasticized material and continuous material flow behavior play a fundamental role to obtain the defect-free weld zone
This results in frictional heating of the part surfaces that causes the polymers in each part to melt in a narrow zone near the surface--the weld zone
. When the parts are sufficiently heated, the vibration stops and the parts are held together in the tooling for a brief period until the weld zone
cools and solidifies.
iQ Servo welder graphs showed the part was acting like a spring because of a hollow area under the weld zone
and was collapsing faster than the horn movement, resulting in inconsistent and leaking welds.
From microscopic examination of the weld zone
and the mechanical property test results, it is concluded that the best bonding is acquired with screw pitched taper stir pin.
When the frequency of the vibrating tool was at 22 Hz the heat generated during the process was more and the melted PP/C30B/EA nanocomposite material gets expelled from the weld zone
. In other words at high frequency of the vibrating tool the melted PP/C30B/EA nanocomposite material does not have enough time to mix again which resulted in poor tensile strength and impact strength.
No matter how high the user increases the pressure in order to deliver more gas flow, PurgeGate prevents too much pressure being delivered to the inflatable dams, but allows the increased flow, should it be required, to achieve a lower oxygen level, or for faster cooling of the weld zone